Excellent work! The shifting-between-worlds mechanic is an awesome way to go “there and back”, and I especially like how the music changes to fit the past and present. The levels are pretty fun, but the leaps of faith started to get a little frustrating by level 8, and even more so on level 9. Also, I thought the radioactive platforms were harmful at first.
Besides that, this game is very good, the story draws me in (with heartbreak!), and you definitely nailed the theme.
If you’ve got the time, I’d appreciate it if you checked out and rated my game, Busy Mind! It’s also a platformer, and it’s got some chill vibes :)